 element library { 
  element book {
   attribute id {text},
   attribute available {text},
   element isbn {text},
   element title {attribute xml:lang {text}, text},
   element author {
    attribute id {text},
    element name {text},
    element born {text},
    element dead {text}?}*,
   element character {
	  mixed {
     attribute id {text},
     element name {text},
     element born {text},
     element qualification {text}}
		}*
  } +
 }
